With Facebook’s frenzied IPO headed toward a huge first-day pop, Mark Zuckerberg, already the world’s youngest paper billionaire, is poised to shoot up the list of the wealthiest people and could catapult past the ranks of well-known, and much older, heavyweights — even fabled investor Warren Buffett.

At the high end, Zuckerberg’s cut of Facebook is worth $19.25 billion after the company raised the price for its initial public offering to a $34 to $38 range. His personal fortune, however, could more than double if Facebook’s shares explode in their first day of trading, similar to LinkedIn’s spectacular debut.

The much-smaller professional social networking company rose a whopping 109 percent in its opening day last year. A first-day bang like that would swell Zuckerberg’s net worth to north of $40 billion.

That personal fortune would propel him past Buffett, the second-richest American with an estimated $39 billion, and Oracle chief Larry Ellison, at No. 3 with $35 billion, according to Forbes. Bill Gates tops the list with an estimated $59 billion.

The Harvard dropout, who turned 28 on Monday, is reaping the rewards from an unlikely beginning in his dorm room. Less than a decade later, he’s ranked 14th on Forbes’ list of richest Americans, ahead of Google co-founders Larry Page and Sergey Brin.

While such a skyrocketing start would likely be the stuff of Zuckerberg’s fantasy, it’s actually a scenario that Facebook’s bankers are trying to avoid.

“Banks generally want a pop in the stock on the opening day, but nobody wants the stock to double,” said one person familiar with the IPO.

“Nobody wants it to seem like we left money on the table,” the person said.

At $38 a share, Facebook is valued at more than $100 billion, and the firm and selling shareholders will raise about $16 billion, making it the third-largest IPO in US history behind Visa and General Motors.

The Facebook founder will sell 30.2 million shares, according to a regulatory filing, and most of the proceeds will be used to pay taxes associated with the exercising of 60 million options.

The precise price of the offering will be determined after the close of trading today, during a conference call that will be attended by Facebook Chief Financial Officer David Ebersmanm, Morgan Stanley’s Michael Grimes and JPMorgan’s Jimmy Lee.

Institutional and retail brokers anticipate the stock offering will be a feeding frenzy; bankers can allocate as many shares in the IPO as they can scavenge. The company has increased the amount of shares being sold by 25 percent to 421 million shares, coming from insiders looking to cash out.

Morgan Stanley has mulled placing a cap on the number of shares average retail investors can purchase to about 500 shares due to the heavy demand.

Other retails brokers including E-Trade, TD Ameritrade, and Charles Schwab also are being overwhelmed by phone calls about the deal.

The extra stock being offered are coming from early shareholders such as Global, which is putting 23 million shares on the block, up from its original 3.4 million.

Venture capital firm Accel will sell 49 million shares, about 25 percent more than planned. Goldman Sachs also will unload more shares than it had first indicated.

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If the hotly anticipated Facebook shares double, Mark Zuckerberg and Bill Gates would be the nation’s wealthiest Americans, with the 28-year-old leapfrogging billionaires Warren Buffett and Larry Ellison. (AP)